PT Journal
AU Van Isacker, P
   Algora, A
   Vitéz-Sveiczer, A
   Kiss, GG
   Orrigo, SEA
   Rubio, B
   Aguilera, P
TI Gamow-Teller Beta Decay and Pseudo-SU(4) Symmetry
SO Symmetry-Basel
JI Symmetry-Basel
PY 2023
BP 2001 - 15pp
VL 15
IS 11
DI 10.3390/sym15112001
LA English
DE Gamow-Teller beta decay; pseudo-SU(4) symmetry; odd-odd N = Z nuclei
AB We report on recent experimental results on beta decay into self-conjugate ( N = Z) nuclei with mass number 58 <= A <= 70. Super-allowed b decays from the J(pi) = 0(+) ground state of a Z = N + 2 parent nucleus are to the isobaric analogue state through so-called Fermi transitions and to J(pi) = 1(+) states by way of Gamow-Teller (GT) transitions. The operator of the latter decay is a generator of Wigner's SU(4) algebra and as a consequence GT transitions obey selection rules associated with this symmetry. Since SU(4) is progressively broken with increasing A, mainly as a consequence of the spinorbit interaction, this symmetry is not relevant for the nuclei considered here. We argue, however, that the pseudo-spin-orbit splitting can be small in nuclei with 58 <= A <= 70, in which case nuclear states exhibit an approximate pseudo-SU(4) symmetry. To test this conjecture, GT decay strength is calculated with use of a schematic Hamiltonian with pseudo-SU(4) symmetry. Some generic features of the GT beta decay due to pseudo-SU(4) symmetry are pointed out. The experimentally observed GT strength indicates a restoration of pseudo-SU(4) symmetry for A = 70.
ER